Mail handling machines conventionally comprise three principal elements: a mail item feed device, a station for franking these mail items arranged at the exit of the feed device (incorporating a weighing device or not), and, arranged at the exit of the franking station, a receiving device, or stacker, for the mail items franked at the franking station. At the present time, these machines can frank mail items of any type and of any format and the receiving device must therefore be able to receive and store all these mail items correctly. This is why such devices are for the most part constituted by a simple receptacle in which the mail items of all formats are stored flat and loose in a pile of small capacity (about 100 envelopes of average thickness), as they are franked. Unfortunately, for high rates, for example around 10000 envelopes per hour (or about 3 envelopes per second), this configuration involves frequent stops of the machine and therefore of the franking of the mail items, when the franked mail items must be removed from the receptacle in order to be placed in post bins of which each presents a storage capacity of the order of 500 envelopes.
U.S. Pat. Nos. 3,945,635 and 5,464,317 disclose automatized stackers which employ conveyors, of the conveyor belt type, disposed lengthwise or perpendicularly at the exit of the franking station, and allowing storage by accumulation of the franked mail items in vertical position, and unloading, without stopping the machine. However, such devices present the drawback of being relatively cumbersome, the storage capacity of these devices essentially depending on the length of the conveyor. In addition, this solution does not dispense with placing these envelopes afterwards in post bins in order to facilitate subsequent handling thereof by the Postal Service.
It is an object of the present invention to provide a mail item receiving device, or stacker, which overcomes these drawbacks. One object of the invention is to propose a receiving device allowing unloading directly into post bins ready for dispatch. Another object of the invention is to allow a modulated reception of items depending on the format of the franked items. Yet another object of the invention is to provide a device which is as simple, compact and ergonomical as possible, while having a sufficient storage capacity, in particular one considerably greater than that of a simple receptacle.